摘要
通过三甲基氯硅烷(TMS)对沸石表面进行修饰,制得了两亲性沸石样品TMS-Hβ,TMS-HY和TMS-HZSM-5,并采用X射线衍射、红外光谱、水饱和吸附量测定和酸碱滴定等手段对改性样品进行了表征.TMS对这三种母体沸石的改性结果有所不同:对于HZSM-5沸石,TMS仅在外表面修饰;对于Hβ沸石,少量TMS进入沸石孔道;而对于HY沸石,TMS则导致沸石结构部分坍塌.两亲性TMS-HZSM-5和TMS-Hβ沸石在乙酸异戊酯相界面水解反应中表现出明显优于各自母体沸石的催化性能.两亲性沸石表面硅烷基的稳定性对其催化性能有一定的影响.相对于TMS-HZSM-5沸石,TMS-Hβ沸石表面硅烷基的稳定性较强;在较高的相界面反应温度下,TMS-Hβ样品仍能维持两亲性能,表现出较高的催化活性.
Amphiphilic TMS-Hβ, TMS-HY, and TMS-HZSM-5 zeolite samples were prepared by modification of the surface of their parent zeolites with trimethylchlorosilane （TMS）. X-ray diffraction, infrared spectroscopy, water adsorption, and titration experiments were used to characterize the surface properties of these modified samples. The modification results by TMS were different on these three zeolites. TMS molecules only covered the external surface of the HZSM-5 zeolite, while part of TMS entered the channels of the Hβ and HY zeolites and even partly destroyed the framework of HY. The amphiphilic TMS-HZSM-5 and TMS-Hβ zeolites exhibited catalytic activity for hydrolysis of isoamyl acetate obviously superior to their parent zeolites. The stability of the alkylsilane on the zeolite surface had an effect on the phase-boundary catalytic performance of the amphiphilic zeolites. TMS molecules covered on TMS-Hβ were more stable than that covered on TMS-HZSM-5. Thus, the TMS-Hβ zeolite maintained its amphiphilic properties at a higher reaction temperature and exhibited a higher phase-boundary catalytic activity than the TMS-HZSM-5 zeolite.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2006年第8期737-742,共6页
基金
国家自然科学基金(20203010)
南京大学开放测试基金(0205001330)资助项目
